Many observers have expressed concern that low voter turnout reflects an acute shortcoming in democratic politics. One proposed remedy, making voting compulsory, has garnered increasing attention among academics over recent years. Our article focuses on some of the technical properties of compulsory voting rules (CVR) while ignoring the philosophical debate over whether voting should be an obligation or a right. Using basic probability analysis, we compare a voluntary voting rule (VVR) to a compulsory one. We show that, under certain conditions, an electoral seat or district can become safer - or less competitive - with the imposition of a CVR. We also discuss some political implications of our analysis. For example, when generalized to, say, the national political system, this result implies fewer competitive seats in a CVR compared to a VVR, everything else equal. We contend that, because fewer seats will be "in play" in a CVR, CVRs should exhibit lower turnover of seats. Also, political suppliers can be expected to more narrowly focus their attention - and resources - on this smaller set of competitive seats than we would expect under a VVR.